Gastrointestinal strictures are abnormal narrowings that have formed in the gastrointestinal tract. Gastrointestinal strictures come in several forms, among them benign and malignant strictures in the esophageal, pyloric, and colonic regions of the gastrointestinal tract. These strictures are undesirable because they interfere with the normal ingestion and digestion of food through the gastrointestinal tract. Such abnormal ingestion/digestion is often accompanied by undesirable side effects, such as gastric ulcer pain, anorexia, nausea, vomiting, discomfort, and Hematemesis.
Gastrointestinal strictures form for a variety of reasons. For example, benign esophageal strictures may be the result of diseases such as peptic esophagitis or gastroesophageal reflux. They may also be the result of congenital conditions, such as the presence of membranous diaphragms or webs in the esophagus. Additionally, they may be the result of injury or scarring in the esophagus due to the ingestion of toxic substances. Malignant strictures, on the other hand, are more often the result of gastrointestinal cancer. For example, one specific type of gastrointestinal cancer called Barrett's esophagus is a result of chronic gastroesophageal reflux disease (stomach acid continually enters the esophagus), and sometimes causes the formation of malignant strictures in the lower portion of the esophagus.
There are presently two known endoscopic methods of treating gastrointestinal strictures. The first is through the use of one or more rigid dilatators. In this method, a rigid dilatator of a selected size is introduced into the gastrointestinal tract through either the oral or rectal orifice and advanced to the stricture location. Once the rigid dilatator is positioned at the stricture location, it is forced through the stricture. Through this application of radial and shearing forces via the rigid dilatator, the stricture tears and/or expands. This first rigid dilatator may then be removed and, if desired, a larger rigid dilatator may then be advanced into the gastrointestinal tract and forced through the stricture. This process may be repeated until the stricture has been sufficiently dilated or altogether eliminated.
One problem associated with this treatment method, however, is that the use of sheer force sometimes causes trauma to the sensitive tissue in the gastrointestinal tract. In addition, the size of a rigid dilator is limited by the cross-sectional area of the portions of the gastrointestinal tract leading up to the stricture. Thus, due to the dilatator's size limitation, it may not be possible to expand the stricture beyond a certain size that is short of that particular gastrointestinal tract portion's normal cross-sectional area.
Another known endoscopic method of treating gastrointestinal strictures is by the use of balloon dilators such as, for example, a wire-guided balloon dilators or a fixed wire balloon dilators. When using a wire-guided balloon dilator, a separate wire is advanced through the gastrointestinal tract to the stricture location. Then, a balloon dilator is advanced over the wire to the stricture location. A balloon at the distal end of the dilator is positioned within the stricture and inflated to a desired size. The inflation fluid is passed from a proximal end of the dilator through the dilator catheter to the balloon. A fixed-wire balloon dilator is similar to the wire-guided balloon dilator except that the balloon is fixed to the end of the wire. Thus, the entire balloon and wire assembly is advanced together through the gastrointestinal tract to the stricture location, where the balloon is then expanded by filling it with fluid.
To inflate the balloon of a balloon dilator, the user may attach a syringe-like device to the proximal end of the dilatation catheter, and then manually inject sufficient fluid into the balloon so that it reaches a desired size. Although such a system can be effective, it includes a number of steps to prepare the system, may require a certain level of manual dexterity and coordination between the user and assistants, and can lead to imprecise inflation of the balloon.
It is accordingly an object of the invention to create a fluid delivery system that is easy to use, precise, and effective.